Isolation and structural characterization of sialic acid-containing storage material from mucolipidosis I (sialidosis) fibroblasts.

Sialic acid-containing storage material was isolated from cultured human mucolipidosis I (sialidosis) fibroblasts by gel permeation chromatography on Bio-Gel P-6 followed by medium-pressure anion-exchange chromatography on Mono Q. The structure determination of the isolated sialyloligosaccharides was carried out by 500-MHz 1H-NMR spectroscopy in conjunction with sugar analysis and analytical HPLC. The storage material showed completely sialylated mono-, di- and triantennary N-glycosidic N-acetyllactosamine oligosaccharides having the Man beta 1----4GlcNAc sequence at the reducing end in common. Heterogeneity occurred with respect to the linkages between terminal sialic acid and the penultimate galactose residues (alpha 2----3/alpha 2----6). It turned out that all the identified carbohydrate chains are consistent with the neuraminidase deficiency.